The present invention relates to a motor-vehicle door latch. More particularly this invention concerns a power-operated such latch with antitheft features.
A standard motor-vehicle door latch has a housing normally mounted on a door edge on which is pivoted a latch fork engageable around a door bolt carried on a door post. A pawl is engageable with the latch fork to hold it in a position engaged around the bolt and, thereby, hold the door carrying the latch closed. Inside and outside handles are normally coupled to a release lever in turn acting on the pawl for opening the latch. A locking lever can block or interrupt the connection between the handles and the release lever to disable one or both of these handles and thereby lock the door. This locking lever is typically operated by a button or lever inside the door and/or a lock cylinder accessible from outside the door.
An antitheft lever in the latch can provide a higher level of security by disconnecting or blocking the release lever so that even a person inside the vehicle cannot unlock the door by means of the standard inside locking button or lever. Only a person with a special key or a particularly coded remote-entry device can use this antitheft feature. Both the antitheft lever and the release lever can further be operated by respective actuators, normally small electric motors, of a central-locking system.
In the newest door latches a small electric actuator, typically a motor, is also provided which serves for power opening of the door. Thus when the door is latched but not locked, actuation of the door handle will trip a switch that in turn operates the opening actuator for effortless unlatching of the door. This is particularly useful in doors having power-latching systems where the door is pulled very tightly closed by the same motor that opens it, so that the person operating the door does not have to exert a large amount of force to tightly close the door or open it. In a so-called keyless entry system when the door is latched and locked, a person carrying a coded transponder operates a door handle to cause the control system to query the transponder and, if the returned code is correct, unlatch and power-open the door.
It is therefore an object of the present invention to provide an improved motor-vehicle door latch.
Another object is the provision of such an improved motor-vehicle door latch which overcomes the above-given disadvantages, that is which has both antitheft and power-opening features.
A motor-vehicle door latch has according to the invention a latch housing, a latch fork pivotal on the housing, a latch pawl movable on the housing between a holding position engaging the fork and preventing pivoting of same and a freeing position permitting pivoting of the latch fork, and a locking lever displaceable coupled with the latch pawl and displaceable between a unlocked position permitting the latch pawl to move into the freeing position and a locked position preventing movement of the latch pawl into the freeing position. A pivotal control member is movable between a power-open position pivoting the latch pawl into the freeing position, an antitheft-on position blocking movement of the locking lever into the unlocked position, and an antitheft-off position permitting movement of the locking lever into the locked position. A drive including a single electrical motor is connected to the control member for pivoting same between its power-open, antitheft-on, and antitheft-off positions.
Thus with this system the already provided motor for the antitheft mode is used for power opening of the latch. The control member allows this single actuator to perform both functions. It is a relatively simple job to program the latch control system for such operation.
According to the invention a release lever is connected between the control member and the latch pawl, although it is within the scope of this invention for the control member to act directly on the latch pawl.
Furthermore according to the invention the control member is pivotal and has an arm engageable directly with the locking lever and at least indirectly with the latch pawl. It can, instead, have two arms one engageable directly with the locking lever and the other at least indirectly engageable with the latch pawl.
The latch according to the invention further has an outside actuating lever and an outside locking lever displaceable between a position coupling the outside actuating lever with the latch pawl and a position decoupling the outside actuating lever from the latch pawl. The control member is pivotal and has a bump engageable with the outside locking lever to displace same into its decoupling position. Furthermore the latch has an outside cylinder coupled to the outside locking lever to displace it between its coupling and decoupling positions. The control member has a cam bump engageable with the outside locking lever for displacement of the member into the antitheft off position on actuation of the outside locking lever by the cylinder.